English verb conjugation
COULD UPTURN

Regular verb: upturn - upturned - upturned

Affirmation

Simple form	V-ing form
I could upturn you could upturn he could upturn we could upturn you could upturn they could upturn	I could be upturning you could be upturning he could be upturning we could be upturning you could be upturning they could be upturning
Perfect	V-ing perfect
I could have upturned you could have upturned he could have upturned we could have upturned you could have upturned they could have upturned	I could have been upturning you could have been upturning he could have been upturning we could have been upturning you could have been upturning they could have been upturning

Negation

Simple form	V-ing form
I could not upturn you could not upturn he could not upturn we could not upturn you could not upturn they could not upturn	I could not be upturning you could not be upturning he could not be upturning we could not be upturning you could not be upturning they could not be upturning
Perfect	V-ing perfect
I could not have upturned you could not have upturned he could not have upturned we could not have upturned you could not have upturned they could not have upturned	I could not have been upturning you could not have been upturning he could not have been upturning we could not have been upturning you could not have been upturning they could not have been upturning

Interrogative form

Simple form	V-ing form
could I upturn? could you upturn? could he upturn? could we upturn? could you upturn? could they upturn?	could I be upturning? could you be upturning? could he be upturning? could we be upturning? could you be upturning? could they be upturning?
Perfect	V-ing perfect
could I have upturned? could you have upturned? could he have upturned? could we have upturned? could you have upturned? could they have upturned?	could I have been upturning? could you have been upturning? could he have been upturning? could we have been upturning? could you have been upturning? could they have been upturning?

Interro-negative form

Simple form	V-ing form
could I not upturn? could you not upturn? could he not upturn? could we not upturn? could you not upturn? could they not upturn?	could I not be upturning? could you not be upturning? could he not be upturning? could we not be upturning? could you not be upturning? could they not be upturning?
Perfect	V-ing perfect
could I not have upturned? could you not have upturned? could he not have upturned? could we not have upturned? could you not have upturned? could they not have upturned?	could I not have been upturning? could you not have been upturning? could he not have been upturning? could we not have been upturning? could you not have been upturning? could they not have been upturning?